小尺度流域河湖水质关联性分析

Correlative Analysis of Water Quality of Small-Scaled River Valley and Lake

选取巢湖潜溪河流域和六叉河流域作为江淮农业小流域代表，采用灰色关联分析（GRA）方法，对比研究小尺度流域人湖河流对河湖交汇区水质的影响。河水及河湖交汇区水质周年变化状况监测结果表明，巢湖水质1a中富营养化最为严重时段是10—12月，营养元素N、P和溶解性金属离子Mn、Fe、Al含量也达到年内最高。河湖水质灰色关联分析结果表明，2个流域河流水质与河湖交汇区水质高度关联，灰色关联度为0．687～0．896。对于小尺度流域而言，湖泊水质对于流域河流水质变化响应迅速，农业流域面源污染对湖泊水体污染的贡献明显。

Non-point source pollution from agricultural watersheds has an increasing contribution to rapid deterioration of downstream water environmental quality in recent years. Two typical agricultural watersheds （ Liucha River valley and Qianxi River valley）, characterized by high grain yield and multi-pond in the Yangtze-Huaihe region of China, were selected as examples to study effect of inflow rivers in small-scaled catchments on water quality in the convergence area of the fiver and lake, using grey relationship analysis （GRA）. Water quality in the rivers and in the convergence area in the lake was monitored twice a month from September 2004 to September 2005. It was found that not only the concentration of TN and TP, but also dissolved metals, such as manganese, iron and aluminum, were the highest in the lake water in the period between October and December in 2004. Grey correlative analysis showed that the water quality in the inflow rivers of the two catchments was highly related to that in the convergence area of the lake with grey correlativity ranging between 0.687 and 0.896. In the case of a small-scaled catchment, water quality in the lake responded rapidly to the variation of water quality in the inflow river, which suggests the non-point source pollution from an agricultural watershed contributes significantly to the pollution of the waterbody of the lake.